Data scanner

ABSTRACT

A system for scanning transversely extending lines of data printed graphically on a document, the system comprising a transversely movable scanning head, means for moving a document longitudinally relative to the scanning head and control means including optical means for finding a line of data to be scanned and stopping such relative movement. The control means may also include switch means for stopping the drive means providing the relative longitudinal movement and a plurality of switch actuator means longitudinally spaced apart to define a plurality of preselected relative positions for the scanning head and such a document. The scanning head carries light source means for projecting light at the data, a light-responsive semiconductor device and optical means for projecting light reflected from such a document toward said device, whereby the concentration of light on said device depends on the presence or absence as well as the width and spacing of graphical symbols in the line of data being scanned.

United States Patent Joseph M. Zappia Miami, Fla.

May 27, 1969 Aug. 17, 1971 Datatype Corporation Miami, Fla.

[72] Inventor [21] Appl. No [22] Filed [45] Patented [73] Assignee [54] DATA SCANNER 59 Claims, 36 Drawing Figs.

Primary Examiner- Daryl W. Cook Attorney-Hood, Gust, lrish, Lundy & Coffey ABSTRACT: A system for scanning transversely extending lines of data printed graphically on a document, the system comprising a transversely movable scanning head, means for moving a document longitudinally relative to the scanning head and control means including optical means for finding a line of data to be scanned and stopping such relative move ment. The control means may also include switch means for stopping the drive means providing the relative longitudinal movement and a plurality of switch actuator means longitudinally spaced apart to define a plurality of preselected relative positions for the scanning head and such a document. The scanning head carries light source means for projecting light at the data, a light-responsive semiconductor device and optical means for projecting light reflected from such a document toward said device, whereby the concentration of light on said device depends on the presence or absence as well as the width and spacing of graphical symbols in the line of data being scanned.

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SHEET 18 0F 12 INVENTOR. JOSEPH M ZAPPI A 2 7 8 5 O 8 4 6 [If w. WI 114 3 n MW 42 I 3 6 W I 2- ww 6 mm ATTORNEYS E DATA SCANNER It is a primary object of my invention to provide a system for scanning data on a document, the system comprising a scanning head arranged for transverse movement relative to such a document, drive means for providing relative longitudinal movement between the scanning head and such a document, control means for the drive means, the control means including means for finding a transversely extending line of data to be scanned, the finding means including means for detecting the presence of a line of data on such a document and deenergizing the drive means to stop relative longitudinal movement between the scanning head and such a document, whereby the scanning head can scan such a line. In the disclosed system, the detecting and deenergizing means includes electro-optical means for detecting indicia printed on a document, the electro-optical means being longitudinally stationary relative to the scanning head. It will be seen, as this description progresses, that the preferred electro-optical means includes a light source arranged to project light at such a document, a light-actuated semiconductor device, and optical means for projecting the light reflected from such a document toward the semiconductor device. It will also be seen that the drive means is arranged to move such a document longitudinally past the scanning head, the drive means preferably including a carriage arranged for longitudinal reciprocation relative to the scanning head and clamp means carried by the carriage and arranged to clamp such a document for movement therewith. 7

It will be appreciated, therefore, that I have provided a system for reading graphically printed data disposed in transverse lines on a document, the system comprising a scanning head arranged for transverse movement relative to such a document, means for moving the scanning head along a line of data at a constant, predetermined rate of speed, light source means carried by the scanning head and arranged to project light at such a document, a light-responsive semiconductor device carried by the scanning head, optical means for projecting light reflected from such a document toward the semiconductor device, the optical means being carried by the scanning head, whereby the concentration of light on the semiconductor device depends on the presence or absence as well as the width and spacing of graphical symbols in the line of data being scanned, an output device, and circuit means for operatively connecting the semiconductor device to the output device.

My system for providing controlled relative longitudinal movement between the scanning head and the document, i.e., the above-mentioned control means for the drive means, preferably includes switch means for deenergizing the drive means to stop such relative longitudinal movement and a plurality of switch actuating means longitudinally spaced apart to define a plurality of preselected relative positions for the scanning head and such a document, each of the actuating means being arranged to actuate the first switch means. Preferably, in fact, the above-mentioned detecting and deenergizing means is disposed in series with the first switch means, whereby, when the first switch means is actuated by one of the actuating means and the detecting means simultaneously detects the presence of a line of data corresponding to the said one actuating means, the drive means will be deenergized.

My system is, therefore, means for reading graphically printed information disposed in transverse lines on a document, the system comprising a scanning or reading head arranged for transverse movement relative to such a document, means for moving the scanning head along a line of data at a constant, predetermined rate of speed, light source means carried by the scanning head and arranged to project light at such a document, a light-responsive semiconductor device carried by the scanning head, optical means for projecting light reflected from such a document toward the semiconductor device, whereby the concentration of light on the semiconductor device depends on the presence or absence as well as the width and spacing of graphical symbols in the line of data being scanned, an output device, and circuit means for operatively connecting the semiconductor device to the output device.

Machines which read letters, e.g., input devices for data processing systems or data transmission systems, have conventionally been developed along two different lines, represented on the one hand by a complicated reader which, at least theoretically, would be able to read even handwritten messages and, on the other hand, by readers arranged to read type of a particular design, i.e., type arranged so that each individual digit, letter or symbol differs as much as possible with any other symbol in the alphabet used, within the limits set by reasonably good readability. The first-mentioned solution, i.e., the apparatus for reading a written message, has proved to be extremely complicated, even for reading only printed digits and letters. It is an extremely hard task for such a machine to distinguish between, for example, a 2 and Z, 5" and S, 0 and Q," 8 and B" or H and either X or I(." This is particularly true if the type for the letters are worn or damaged or if the recording is otherwise impaired, in which case a reasonably reliable result can only be obtained with an extremely complex and, therefore, very expensive machine.

The other method of machine reading, namely modifying the type itself, for example, by dividing the type in several distinct vertical fields or by providing the type with additional or enlarged portions, makes it comparatively hard visually to read the type in a normal manner. In any event, such a type looks strange and unfamiliar to anybody who sees it for the first time and thus causes a reduction of reading speed and reading reliability. This is, of course, a distinct disadvantage, especially if the message recorded consists of digits, if the message is in an unfamiliar language, or if the message is coded. This situation is frequently encountered in important message transmitting systems, such as military communications systems or long-distance telecommunication systems.

My data scanner may be used to read data which is produced by an ordinary typewriter which is modified to provide, as well as conventional letters or symbols, a printed code representing the letters or symbols. Preferably, each type carrier will be modified so that there will be printed either below or above each letter or symbol marks which can be read by my scanning system. Preferably, as will be more fully explained hereinafter, the marks will have the shape of one or more rectangular fields. In fact, a conventional typewriter key may be easily modified to provide a machine-readable recording in accordance with the present invention. That is, there is sufficient space on the conventional type carrier of a typewriter, below the character on the type carrier, for providing a line of protruding marks, e.g., short vertical lines and/or rectangular fields of different width, which, for example, in a five or six place binary code system, gives a machine-readable representation. Thus, the basic binary recording consists of the presence or absence, respectively, of a vertical line in any of a number of predetermined positions. Adjacent lines may preferably join one another to a rectangular field, the width of which will be dependent on the number of lines.

It will be seen, as this description progresses, that I prefer that the machine-readable information correspond to the Baudot code. The manner in which this may be accomplished will be explained in greater detail hereinafter.

It is an object of my invention, therefore, to provide a system for scanning and reading data on a document, which system comprises a scanning head arranged for transverse movement relative to such a document, drive means for providing relative longitudinal movement between the scanning head and such a document, control means for the drive means, the control means including first switch means for deenergizing the drive means to stop such relative movement, and a plurality of switch actuating means longitudinally spaced apart to define a plurality of preselected relative positions for the scanning head and such a document, each of the actuating means being arranged to actuate the first switch means.

Another object of the present invention is to provide such a system in which the control means includes means for finding a transversely extending line of data to be scanned, the finding means including means for detecting the presence of a line of data on such a document and deenergizing the drive means to stop relative movement between the scanning head and such a document, whereby the scanning head can scan such a line. Preferably, as will be more fully explained hereinafter, the detecting and deenergizing means is disposed in series with the first switch means for deenergizing the drive means, whereby, when the first switch means is actuated by one of the said actuating means and the detecting means simultaneously detects the presence of a line of data corresponding to the said one actuating means, the drive means will be deenergized.

Another object of the present invention is to provide such a system in which the drive means is arranged to move the document longitudinally past the scanning head, the drive means including a carriage arranged for longitudinal reciprocation relative to the scanning head and clamp means on the carriage and arranged to clamp such a document for movement therewith. It will be seen, as this description progresses, that the clamp means includes a clamp member mounted on the carriage for movement between a document engaging position and a document releasing position, spring means for yieldably urging the clamp member to its document engaging position, latch means for holding the clamp member in its document releasing position in opposition to the spring means, the latch means being supported by the carriage, means for cocking the latch means, the cocking means being disposed adjacent one end of the travel of the carriage, and means for releasing the latch means, the releasing means being disposed adjacent the opposite end of the travel of the carriage. The cocking means may be an abutment disposed in the path of movement of the latch means and arranged to cock the latch means when the carriage reaches the said one end of its travel. The releasing means, in the illustrative embodiment, includes a solenoidoperated means effective, when energized, to release the latch means.

Another object of my invention is to provide such a system including means for detecting the presence ofa document and energizing a solenoid when such a document is in position to be engaged by the clamping means, the solenoid being operatively connected to the clamping means.

A further object of my invention is to provide such a system including a solenoid-operated stop arranged to position such a document to be engaged by the clamping means, the solenoidoperated stop being movable, when actuated, to a position out of the path ofmovement of such a document.

Another object is to provide a frictional drive roller for engaging and moving a document longitudinally past the scanning head, the drive roller being positioned and arranged to continue to move a document longitudinally after the aforementioned clamp is moved to its document releasing position and the carriage on which the clamp is mounted is returned to its initial starting position. That is, the movable clamp arrangement is provided for moving the leading edge of a document to the point where it can be engaged and moved continually longitudinally past the scanning head by the friction drive roller.

Still another object of my invention is to provide a pin setting mechanism for use in combination with the line finding means discussed previously, thereby to scan selected lines of data on a document.

Other objects and features of the present invention will become apparent as this description progresses.

To the accomplishment of the above and related objects, the present invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings and description are merely illustrative and that change may be made in the specific constructions illustrated and described so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 schematically shows the word DATA" recorded for visual as well as machine-reading in accordance with the concept of my invention;

FIG. 2 shows the letters A and D recorded with a visual and machine-readable representation, as well as the machinereadable representations of the machine functions space and carriage return;

FIG. 3 shows a representation of the letter D" preceded by a particular sign signifying beginning of line or line feed";

FIG. 4 shows the visual and machine-readable representation of the sign period FIG. 5 shows a type carrier or a part thereof adapted to provide a visual as well as a machine-readable representation;

FIG. 6 shows how a recording made with the type carrier of FIG.' 5 may appear on the record carrier, i.e., conventional paper;

FIG. 7 shows a line of data defined by visual as well as machine-readable characters;

FIG. 8 is a block diagram of a pulse shaping and recording circuit utilized in my data scanning system;

FIG. 9 is a pulse diagram of a number of representative signals utilized in and produced by a circuit, such as the circuit of FIG. 8;

FIG. 10 schematically illustrates, in a very simplified manner, a mechanical embodiment of my data scanning system;

FIG. 1 1 is a schematic showing, in detail, portions of the circuit of FIG. 8;

FIG. 12 is a perspective view ofa working model of my data scanning system;

FIG. 13 is an enlarged, fragmentary view of the portion of the system on which a document is initially placed;

FIG. 14 is an enlarged, fragmentary sectional view taken from FIG. 13 generally along the line 14-14;

FIG. 15 is a fragmentary, perspective view, greatly enlarged, of the scanning or reading head of my system and the means on which the scanning head is mounted;

FIG. 16 is a fragmentary, perspective view of the chain which is used in the drive for the scanning head;

FIG. 17 is an enlarged, fragmentary sectional view of the scanning head and the means on which it is mounted;

FIG. 18 is a somewhat diagrammatical view of the driving system for the scanning head;

FIG. 19 is an enlarged, fragmentary sectional view taken from FIG. 17 generally along the line 19-19 and showing the arrangement of the optics in the scanning head;

FIG. 20 is a perspective view of one of the diaphragms used in the optics of the scanning head;

FIG. 21 is a fragmentary, plan view of the optics portion of the scanning head and showing the scanning head above a document;

FIG. 22 is a fragmentary, sectional view taken from FIG. 23 generally along the line 22-22 and showing the solenoidoperated stop used to position documents on the system;

FIG. 23 is an enlarged, fragmentary and partially cut-away plan view of the system of FIG. 12 and showing the relationship of the scanning head drive system with the document drive system;

FIG. 24 is a fragmentary, sectional view showing the document clamping means of the present invention latched in its document-releasing position;

FIG. 25 is a view similar to FIG. 24 except that the carriage on which the clamping means is mounted is at the opposite end of its travel and the clamping means is in its document-engaging position;

FIG. 26 is a fragmentary, sectional view, partially broken away, showing a friction driving system for the document as well as the chain drive for the carriage on which the clamping means is mounted;

FIG. 27 is a fragmentary, sectional view showing the carriage and the bar on which the carriage is movably supported and the switch-actuating means for stopping the carriage at selected points along its travel;

FIG. 28 is a fragmentary, sectional view showing switch-actuating means which is slightly different from that shown in FIG. 27;

FIG. 29 is a fragmentary, sectional view of still another type of switch-actuating means for stopping movement of the carriage, the system of FIG. 29 including means for manually selecting points at which the carriage will stop;

FIG. 30 is an enlarged fragmentary, sectional view of still another type of switch-actuating means for stopping the carriage at selected points;

'FIG. 31 is a view, similar to FIG. 30, except showing the switch-actuating means in a different position;

FIG. 32 is a fragmentary, perspective view, partially sectioned and cutaway, showing a plurality of the switch-actuating means illustrated in FIGS. 30 and 31;

FIG. 33 is a sectional view taken from F 1G. 32 generally along the line 33-33;

FIG-34 is a fragmentary, sectional view showing double clamps for engaging a document;

FIG. 35 is a schematic of an illustrative control circuit for my system; and

FIG. 36 is a block diagram of the logic associated with the scanning head.

In FIG. 1 the word DATA" is shown, such as it may appear recorded with visual as well as machine-readable symbols. The recording may be a graphic recording on any suitable record carrier such as a sheet of paper, card or tape of paper or other suitable materials. The type may, of course, be of any suitable shape.

Below each typed letter is a representation in a machinereadable code, which representation, however, could have been made above the letter if required in some particular machine. The machine-readable information is preferably in a line parallel with the visually readable graphic symbols. For several reasons it will be convenient to leave a space between the two types of information so that their outlines do not run into one another. One reason for this is that, without such a space, the visual reading may be difficult. Also, there is a risk that the reading machine might pick up the wrong information from parts of the letters.

Each of the symbols may be represented by a machinereadable 6-bit code represented by a presence or absence in the respective positions l-6 of a'registration. In the illustrative example, the positions are numbered from left to right. In FIG. 1 the machine-readable representation of the letter D" is made up in the following way:

There is one registration in the position I, no registration in the position 2, one registration in the position 3, one registration in the position 4, no registration in the position 5 and one registration in the position 6. In the following description, and for illustrative purposes only, the machinereadable code for each letter is designated by a 6-bit binary number where a binary l represents the presence of a printed mark and the binary 0 represents the absence ofa printed mark. The designation x in any position represents either a binary l or a binary O and the sign is used to separate two code groups from one another. The code for the letter D" is thus 1 0 l l O 1" and the code for the entire word DATA in FIG. 1 is l 0 l 1 O 1/1 00 l 1 1/1 1 I l 0 0/1 0 0 1 1 1.

For reasons which will be apparent from this description of the data scanning system, all groups in the chosen code are of the type lxxxxx. Nonpermissible codes are thus the codes Oxxxxx," Ooxxxx, O00xxx, OOOOXx, OOOOOx and 00OOO0.From this it should be apparent that, in the illustrative example, only the code positions 2-6 carry variable information. If the reading and evaluation apparatus does not have a memory function, the alphabet then may only comprise at most 25 different symbols for this representation. In many cases, the receiving and/or the evaluating apparatus is provided with a memory thus making it possible to use a particular symbol to switch between different subsets of the alphabet. This possibility is, for example, made use of in telex apparatus where the switch between lower case" and upper case is transmitted as a particular machine-controlling letter implying a switch between two different subsets of the alphabet, e.g. the subsets lower case and upper case." As is well known, an alphabet with limited variance for each letter, such as, for example, a 5-bit code for each letter, may be. used for transmitting an alphabet of any variance provided that the transmitting and receiving equipment is organized accordingly. It should therefore be realized that, even with a 5-bit code, the system of my invention is not limited to a 25-symbol alphabet.

In fact, my data scanning system is ideally suited for use with the Baudot code, i.e., five data bits plus start and stop bits, conventionally used in teletype and telegraph equipment.

The illustrated 6-bit code representation for each letter is therefore to be considered a matter of convenience which, for usual type size, paper quality, manufacturing accuracy for the type-carrier and the separating capacity of the reader, may be considered practical. This choice is, therefore, not a primary characteristic of the invention.

It is obvious that, apart from very simple information transmitting systems, machine governing functions or machine orders have to be transmitted as well as the letters of the alphabet which are to be printed. Thus, my data scanning unit must read and recognizecertain codes representing machine functions. FIG. 2 shows an example of one code. Between the code for the letter A is thus a code for space" which may be represented in binary as l l 101 1. After the letter D" the function carriage return" may be represented in a similar manner by the binary representation 111101. This code I 1 l 101 thus terminates each line on the record carrier.

FIG. 3 shows a code example which may represent the beginning of a line. The code 110111 which precedes the letter D may be interpreted in different ways, depending on which kind of typewriter or printing device is actually used. In a system where the line feed takes place automatically after carriage return, the code 11011 I may be interpreted as signifying the beginning of a line. If the carriage return takes place without a line feed, the symbol group 1 10111 may represent the machine order or function line feed. In this case, the preceding letter D" on the same line, having the code representation 10] 101 is not the information which is to be read after the line feed, but rather an information in a corresponding place on the next line. This will, however, be more fully explained in connection with FIG. 10.

FIG. 4 illustrates that not only letters, but also signs, e.g., periods, commas, etc., may and should have a machine-readable representation. In the example shown the sign period is represented by the code group l 1 lOOO.

FIG. 5 illustrates a part of a type carrier 10 which, in the embodiment shown, is intended to print the upper case letter D and which is provided with means for producing a machine-readable representation of the letter as well. The type carrier 10 is, therefore, in the usual manner provided with a raised portion 12 in the shape of a mirror image of the letter D. Under this portion 12 is a line comprising three rectangular protruding portions 14, 16 and 18. The portion 14 corresponds to the desired registration in position 6," the portion 16 corresponds to the registration in the positions 4 and 3 while the portion 18 corresponds to the desired registration in the position l The space between portions 14 and 116, and the space between portions 16 and 18 correspond to the desired absence of registration in positions 5 and 2 respectively. The type carrier 10 may be of any conventional type, depending on which kind of typewriter is modified. Further, the carrier 10 is intended to represent a piece of a type ribbon or a type wheel or even a piece of a printing machine type.

FIG. 6 shows how the character D and its coded representation might appear on the record carrier when printed with a type carrier, for example, according to FIG. 5 via an intermediate ribbon or ink sheet or the like. The character is built up of the shape 12', forming the letter D, and the three registrations 14, 16' and 18 corresponding to the binary code representation chosen for the letter D. As will be seen, the borderline of the character 12 may have imperfections 20 and the borderline of the code representation 14l8 may have imperfections 22. These imperfections which are normally present in a recording make the machine reading of data rather difficult as will be further described hereinafter.

FIG. 7 shows, in an exaggerated scale, the text data type recorded to be machine read. The letter D in the word DATA is preceded by a registration 24, signifying start of line or line feed as described in connection with FIG. 3. Between the words DATA and TYPE is a code group 26 signifying space. The last letter E in the word TYPE" is followed by a code group 28 also signifying space and the sign period The line ends with the sign 32 signifying carriage return with or without line feed depending on the system chosen. The lines 36, 38 and 40' as well as the points 34 and 34' refer to the reading head movement for reading the coded characters as will be further described hereinafter. The registration is made on a data carrier or document 40 which may be of any suitable kind and which, in its simplest form, may be an ordinary typewriter sheet.

FIG. 8 is a block diagram of an electronic reading and discriminating circuit for evaluating the output from a photoelectric reader of my data scanning system. The circuit has an input 90 feeding a conventional amplifier 91. The amplifier 91, as well as the elements of the rest of the circuit, may have transistors as amplifying elements, the transistors being fed from source voltages of conventional levels. The output from the amplifier 91 is fed to the input of an amplitude sensitive pulse shaper 92. The shaper 92 may be a Schmidt-trigger or similar device of the type which has one output voltage, e.g., a low voltage, when the input is below a predetermined threshold value, and a different output voltage, e.g., a higher voltage, when the input is above the threshold value. The transition between the two different output states has to be fast in order to provide output signals with steep flanks from a slowly varying input signal. The reason for the use of such an amplitude sensitive pulse shaper will be described in more detail hereinafter.

The output from the Schmidt-trigger 92 is connected to the input of a monostable multivibrator or one-shot pulse generator 93 having two different output states, which will be designated and 1 respectively. In the absence of an input signal the monostable multivibrator 93 will be in its rest state or zero state at which it produces an output signal 0. Upon the arrival to its input of a signal having sufficient steepness and amplitude, the monostable multivibrator changes its internal state and produces an output signal 1 during a time interval which is determined by an internal time constant. Conventionally, a resistor-capacitor network determines the time constant. As will be explained later, the time constant of the multivibrator 93 is comparatively long in terms of the pulse repetition frequency of the input signal to the amplifier 91.

The output signal from the multivibrator 93 is supplied as input signal to an astable multivibrator or gated multivibrator 94. As long as the multivibrator 94 is supplied with a high input signal, i.e., an input signal of value l it switches between the 0 and l state and produces an output signal which varies accordingly. The pulse repetition frequency as well as the pulse length of its output signal is determined by parameters of the multivibrator 94, usually by resistor-capacitor combinations. In the illustrative embodiment, the multivibrator 94 is arranged to produce six pulses during the time interval when the output from the multivibrator 93 produces an output of the value I," and the multivibrator 94 will not produce anything but a 0 output signal during the pulse interval between consecutive output pulses from the multivibrator 93.

The output from the multivibrator 94 is fed to one input terminal of an AND gate 95, the second input of which is taken from the output of the amplifier 91. The output from the AND gate will thus be a chopped signal with alternate periods in the 0" state and the logical product of the 1 state from the multivibrator 94 with the output from the amplifier 911 respectively. This output signal may be integrated in a resistorcapacitor-integrator or low-pass filter 96 having a time constant approximately of the same order as the pulse length of the output pulses from the multivibrator 94. This filters out any transients of higher frequency which may be caused by a number of different noise sources in the mechanical and optical system connected to the electronic reading and evaluating circuit, by imperfections in the document being read, or by an external noise source. The output signal from the integrator 96 will thus essentially be a saw tooth signal, the relevant portions of which will be of two kinds, namely a signal of comparatively high peak amplitude corresponding to a high output from the amplifier 91 and a signal of comparatively lower amplitude,corresponding to a low output from the amplifier 91. Any possible transient signals of high amplitude, but of very short duration, which may be present in the output signal from the amplifier 91, will be filtered out by the integrator 96.

The output signal from the integrator 96 is fed to the input terminal of a pulse shaper and discriminator 97, which may be a Schmidt-trigger of essentially the same type as the Schmidttrigger 92. The threshold level at which the output from the Schmidt-trigger 97 switches from the O to the 1 state.or from the 1" to the 0 state respectively is preferably selected to give a reliable output pulse while, at the same time, suppressing or not reacting to, the low amplitude pulses between the significant saw tooth pulses.

The output pulses .from the pulse shaper and discriminator 97 may be fed directly to the input of an AND gate 98, or the pulses may first be given equal pulse length by means of an intermediate monostable multivibrator 97'. The use of the intermediate monostable multivibrator 97' adds more complexity to the circuitry, but, it also contributes to the reliability of the readout in case the pulse width at the chosen discriminating level of the substantially saw tooth-shaped pulses from the integrator 96 varies significantly.

In the illustrative circuit, the other input to the AND gate 98 is taken from the output of a monostable multivibrator 94 having a comparatively short pulse time. The input to the monostable multivibrator 94' is derived from the output of the multivibrator 94. The multivibrator 94' is preferably further provided with an input delay to prevent it from being triggered by the fall of the output signal from the multivibrator 94 to produce an output pulse of short duration and of the state l at the instant of time when the output from the Schmidttrigger 97 (or the multivibrator 97') is most probably in the state l if the chopped output signal from the AND gate 95 is in the state I. In other words, the time of occurrence of the output signal from the multivibrator 94 or from the multivibrator 94 is chosen so that a reliable sampling pulse is fed to the input of the AND gate 98 whenever an output pulse from the Schmidt-trigger 97 or the multivibrator 97' may be expected.

In the illustrative embodiment, the output from the AND gate is connected to the input of a further monostable multivibrator 99 of approximately the same type and having the same time-determining parameters as the monostable multivibrator 93. The output from the monostable multivibrator 99 constitutes the information carrying output signal from the circuit and may be used to operate auxiliary output devices, such as an electric typewriter, an input device to a computer or a terminal device for receiving or transmitting information in an information transmitting system of any kind.

The operation of the circuit of FIG. 8 will now be further described with reference to FIG. 9, which shows various pulse and signal shapes typical for the operation of the circuit in connection with a photoelectric reader. The letters A, B, C, D, E, F, G and H in FIGS. 8 and 9 indicate the points at which a voltage level is sampled (FIG. 8) and the voltage curve at the respective points (FIG. 9).

Thus, the shaded generally rectangular fields designated A in FIG. 9 may represent a portion of a record carrier passing under a photoelectric reading head. It will be noticed that this is how the machine-readable portion designated XA in FIG. 1 under the letters DA in the word DATA would appear to the photoelectric reader. For this reason the light and dark spaces have not been numbered accordingly.

Since it is inevitable that a pencil of reading light, as will be explained hereinafter, will have a definite, but small cross section, and because of delay and limited band width of the photoelectric reader and the amplifier 91, the output signal from the amplifier cannot be expected even to approach the pulse shape of a proper square wave. The best which may be obtained is an output voltage or current from the amplifier 91 having a pulse shape similar to the curve B in FIG. 9. Noise and disturbances have been left out of curve B, but it will be understood that this signal hardly may be expected to be noise free, and that one object of my invention is to provide an electronic reading and evaluating circuit which will compensate for noise and similar disturbances which may have a rather large amplitude but be of short duration.

The combination of the Schmidt-trigger 92 and the multivibrator 93 generates a comparatively long pulse, i.e., a pulse of sufficient duration to cover the time span when the code positions of an entire character pass under the reading or scanning head of the photoelectric reader. More specifically, the multivibrator 93 has to provide a deblocking signal to the multivibrator 94 to allow this multivibrator 94 to generate exactly six pulses of predetermined pulse width and pulse interval, which pulses are used as clock signals for the entire circuit.

The output signal from the monostable multivibrator 93 is represented by the curve C of FIG. 9'. It is assumed that the Schmidt-trigger 92 generates an output signal as soon as the output voltage B from the amplifier 91 has reached a predetermined value, indicated by the dotted line designated V in the curve B. The leading edge of the curve C is concurrent with this time instant, since any delay will be very small.

The trailing edge of the output signal from the monostable multivibrator 93 may fall anywhere between the time instant when the sixth pulse in the pulse train D has been initiated and the time instant when a seventh pulse would have been initiated. A'suitable and safe design would be to have the pulse of the curve D fall at the trailing edge of the sixth pulse in each pulse group of the pulse train D. Thus if the pulse width of the pulses in the pulse train D arbitrarily is assigned the value 1 T (one unit of time) the pulse width of the pulse C will be I l T l 1 units of time). It will be understood that, in this case, one unit of time will be equal to half the nominal duration of a single light or dark space under the reading head as shown in the curve A.

The clock pulses from the multivibrator 94 are fed to one input of the AND gate 95, the other input of which is fed from the output of the amplifier 91. The output from the AND gate 95, in its turn, is supplied to the input of the integrator 96.

In this connection it has to be pointed out, that the AND gate and integrator shown in FIG. 8 are to be interpreted as functions. Thus, the output from the amplifier 91 may preferably be fed via a resistor R to a capacitor C as shown in FIG. 11. In parallel with the capacitor C is a transistor T, the base electrode of which is fed from the output of the multivibrator 94. The polarity of the output and the biasing of the transistor T is chosen to have the transistor conduct and short circuit the capacitor C in the intervals between the (positive) pulses of the pulse train D. The circuit of FIG. 11 will perform in the manner shown by the AND gate 95 and integrator 96 in the block diagram of FIG. 8, and will produce an output waveform E in FIG. 9 from the input waveform B, which essentially is a saw tooth curve, the leading edge of which is determined by the product R C and the trailing edge of which is determined by the product R of the transistor T with the capacitor C.

The time constant of the R C combination may be of the order I T, where T is the arbitrary unit of time mentioned before and based on the pulse width of the pulses in the pulse train D.

The requirements on the summing or chopping and integrating circuit is to filter out noise and transients and at the same time to translate the waveform B, i.e., the output from the amplifier 91 into a pulse train with well defined pulses of maximum time-voltage integral at the instant of the actual signal, while at the same time discriminating between signa and absence of signal.

The Schmidt-trigger 97, which follows the AND gate integrator 95, 96 may be adapted to switch at the amplitude V: of the pulse train E to produce an output shown by the curve F of FIG. 9. This signal, the pulses of which may be of different width and generally shorter than 1 T, may be used directly as one input to the AND gate 98, but, as mentioned previously, some advantages may be obtained by using the intermediate multivibrator 97', which may make all pulses of equal length of approximately the length l T. This increases the reliability of the circuit.

Leaving the function of the monostable multivibrator 97 and the AND gate 98 for a moment, it will be seen that the output from the multivibrator 94 is connected to the input of the multivibrator 94', whose function it is to provide a sampling or strobing pulse for the AND gate 98. Although the maximum amplitude of the pulse train E is concurrent with the fall or trailing edge of the pulses in the pulse train D, the optimum sampling instant, as far as reliability is concerned, is somewhat earlier in time, irrespective of whether the pulses F are taken out directly from the output of the Schmidt-trigger 97 or are reshaped by the monostable multivibrator 97'. For this reason, the triggering of the monostable strobing or sampling multivibrator 94' is delayed with respect to the leading edge of the pulse train D to take place at the time 0, 7-0, 8 T from the leading edge. This is at the probable maximum or on the median of the surface of the information carrying pulses in the pulse train F. The monostable multivibrator 94' could, however, be used to make this median concurrent with the trailing edges of the pulses in the pulse train D, and thus make the delay element, or even the multivibrator 94' itself superfluous. How this could be accomplished is, however, more a matter of design and will not be explained further here.

The pulse length of the output pulses from the multivibrator 94' or from, for example, a differentiating and clipping circuit between the output of the multivibrator 94 and the AND gate 98 is preferably of the order 0, l T.

Thus, the output from the AND gate 98 will also be pulses of similar short duration, but occurring only at time instances when corresponding pulses are present in the F pulse train.

The output pulses from the AND gate 98 finally trigger the monostable multivibrator 99, the pulse length of which may also be of the order 1 T. The output pulses from the multivibrator 99 are the output pulses of the circuit and correspond to the information read by the photoelectric reader. It will be realized that this pulse train H in Fig. 9 will contain information pulses of predetermined pulse length, determined by the parameters of the multivibrator 99, the leading edges of which are spaced from each other by multiples of a predetermined time interval, determined by parameters of the multivibrator 94.

The output pulses I-I may be temporarily stored in a register (not shown) preferably by being read serially into a shift register and the output or outputs may be connected to any suitable output/equipment, such as a displaying, recording or transmitting device.

FIG. 10 shows the more important parts of reader or data scanning system according to my invention. The reading head, indicated at 42, is travelling during the read movement at a constant, predetermined speed along the selected line on the record 40. The driving means for the reading head 42 may be a synchronous motor 111 which is energized from a suitable AC source. The motor 111 may drive a lead screw 111 to which the reading head 42 may be drivingly coupled for movement in the direction of the arrow 117. As will be appreciated, means (not shown) must be provided for releasing the reading head 42 from the lead screw 111' so that it can be returned in a direction opposite to arrow 117 to its home position. For instance, solenoid-operated means for threadedly engaging the screw 111' may be mounted on the head 42 and arranged, when energized, drivingly to couple the head and motor 1 11.

The document or record feed may be accomplished by a servomotor 112 controlled by a servoamplifier 113, the input of which is connected to a photocell (not shown) in a recess of the reading head 42. This photocell serves as line finder, keeping the reading head 42 travelling along the line 110 irrespective of any skew of the line with respect to the normal line of travel of the reading head. The details of a line finding means will be more fully discussed hereinafter.

When the reading head 42 has reached the end of the line 110, which may be determined either by a limit switch (not shown) or by a circuit connected to the output signal of the multivibrator 99 and responsive to the code signifying carriage return" and/or line feed, as previously explained, a signal is generated. This signal is used to block or inhibit the output from the reading circuit and also to disconnect the head 42 and motor 111. Then, the reading head 42 will return in the direction opposite to the arrow 117 to its home position. When the reading head 42 has returned to this home position, or during the return travel of the reading head, an incremental signal is fed through conventional means 113 to the input of the servoamplifier 113, causing the output from the amplifier to drive the servomotor 112 to turn the illustrated roller 114 which supports an endless belt 115 on which the record carrier 40 is arranged. Thus, the belt 115 moves in the direction of the arrow 116 until a new line 1111' comes under the reading head 42.

The relative longitudinal or feeding movement between the record carrier 40 and the reading head 42 may, for example, take place in either of the two modes shown in FIG. 7. That is, the relative movement may be as indicated at 38' or as indicated at 40'.

The record carrier 40 may be provided with sprocket holes (not shown) along the edges, in which case the feed mechanism may be simplified and take the form of a step mechanism for the line feed, provided that the sprocket holes have a definite location relationship relative to the lines. That is, an integral number of sprocket holes must be provided for an integral number of lines. A suitable and preferred feed drive means will be discussed hereinafter.

The most important or critical requirement on the reading apparatus, however, is that the transverse travelling speed of the reading head 42, i.e., in the direction of the arrow 117 in FIG. 10, bears a definite, predetermined relationship to the pulse repetition frequency of the multivibrator 94 of FIG. 8, thereby to enable the electronic reading and evaluating circuit to give an accurate translation of the information read into a pulse train H. Normally this may be secured by adjusting the pulse repetition frequency of the multivibrator 94 manually, but it is also possible to use the speed of the motor 111 to generate a control signal, which may be used automatically to adjust the pulse repetition determining parameter or parameters of the multivibrator 94. This is, however, a matter of design and should be obvious to one skilled in the art.

Referring now to FIG. 12, it will be seen that I have illustrated a practical embodiment, indicated generally by the reference numeral 122, of my data scanning system. A document, such as indicated at 124 in FIG. 13, is placed on the bed 126 portion of the system 122 to be against a stop 128 and a left-hand (FIG. 13), longitudinally and vertically extending wall 130 bounding the bed portion 126. When the document 124 is against the stop 128, it is in a position to be engaged by a clamp 132 which is arranged to hold the document on a carriage 134 (best seen in FIG. 23) which moves the document in the direction of the arrow 136.

The carriage 134 is mounted for longitudinal reciprocation on a longitudinally extending guide bar 138, the cross section of which is best seen in FIG. 27.

Specifically, the carriage 134 moves the document 124 in steps, determined by the distance between lines of data printed on the document, in the direction of the arrow 136. That is, the carriage 134 advances the document 124 in a stepby-step manner in the direction of the arrow 136, stopping the document at a plurality of selected positions so that a transversely moving scanning head of the system can scan transversely extending lines of data on the document. Preferably, each line of data on a document 124 will extend perpendicularly to the direction of movement of the carriage 134.

The stop 128 is operatively connected to a solenoid as illustrated in FIG. 22, the solenoid being arranged so that, once the stop 128 has served its function of stopping the document 124 in a position to be engaged by the clamp 132, the stop can be moved to its illustrated broken-line position (FIG. 22) to be out of the path of movement of the document. As illustrated, the stop 128 may extend upwardly through an opening 142 in the bed 126.

I prefer to energize the solenoid 140 by means of an electrooptical device, such as illustrated in FIG. 14 and indicated generally by the reference numeral 144. The electro-optical device 144 comprises a light source 146 arranged to project light through an opening 148 in the bed 126 at a light-responsive device 150. The device 150 may be any conventional light-responsive device such as, for instance, a light-actuated silicon controlled rectifier or a light-actuated diode. When the document 124 is in its proper position on the bed 126, i.e., against the stop 128 and the wall 131 as illustrated in FIG. 13, the document will block the light projected through the opening 148 to cause the device 150 electrically to change state. As will be more fully discussed hereinafter, when the device 150 so electrically changes state, the solenoid 140 is operated to lower the stop 128.

Further, the output of the electro-optical device 144 is used to actuate the clamp 132. Specifically, as will be discussed in conjunction with the schematic of FIG. 35, a solenoid 152 is operatively connected to the device 150 and arranged, when the device electrically changes state, to actuate the clamp 132. The solenoid 152 operates a lifter 154 illustrated in FIGS. 23, 25 and 35. Referring to FIG. 25, it will be seen that, when the lifter 154 is moved from its illustrated solid-line position to its illustrated broken-line position, the clamp 132 is moved from its document-releasing position to its document-engaging position.

The bed 126, which extends in the direction of the arrow 136 substantially throughout the length of the system 122, is provided with an elongated slot 156 in which the clamp 132 moves. This slot is best seen in FIGS. 24, 25 and 27. Referring to these figures, it will be seen that the clamp 132 is mounted for pivotal movement on the carriage 134 about an axis 157 and that a pinion gear 158 is journal mounted on the carriage for rotation about the axis 157. The pinion gear 158 and the clamp 132 are connected so that rotation or rocking of the pinion gear produces pivotal movement of the clamp. A spur gear 159 is journal mounted on the carriage 134 and meshed with the pinion gear 158 and a spring means 160 is provided for yieldably urging the spur gear in one direction about its axis to hold the clamp 132 in its document-engaging position, the illustrative spring means 160 being a tension spring connected to the carriage 134 as indicated at 161 and to the spur gear 159 as indicated at 162. Latch means, indicated generally by the reference numeral 163, is provided for holding the spur gear 159 in opposition to the spring 160, thereby to hold the clamp 132 in its document-releasing position. The illustrative latch means 163 comprises a member 164 mounted on the carriage 134 for pivotal movement about an axis defined by the pin 165, a leaf spring 166 connected to the member 164 as indicated at 167 and arranged to engage an axially extending pin 168 carried by the spur gear 159. A hook element 168 is connected to the member 164 as indicated at 169. This hook element 168 is provided with a hook portion 170 arranged, when the member 164 is in its FIG. 24 position, to engage a pin 171 carried on the carriage 134. Specifically, an abutment or stop 172 is placed in the path of movement of the member 164 at the end of the travel of the member in the direction of the arrow 136 to provide means for cocking the latch means 163 to hold the clamp 132 in its document-releasing position. That is, movement of the member 164 in the direction of the arrow 136 after it engages the abutment 172 will rotate the spur gear 159 in a clockwise direction (FIGS. 24 and 25) in opposition to the spring 160 to move the clamp 132 to its document-releasing position. When the member 164 is pivoted an amount sufficient to permit the hook portion 170 to engage the pin 171, the member 164 will be held in its FIG. 24 position. It will be seen that the hook portion 170 is provided with a cam surface 174 which, when the member 164 is pivoted counterclockwise, (FIG. 24), will raise the hook portion 170 so that it can drop into engagement with the pin 171.

When the carriage 134 is at the beginning of its travel, i.e., the position illustrated in FIG. 25, the latch system 163 is released by movement of the lifter 154 upwardly to lift the hook portion 170 out of engagement with the pin 171. When the hook portion 170 is so disengaged from the pin 171, the spring 160 will rotate the spur gear 159 to move the clamp 132 from its document-releasing position to its document-engaging position. The condition of the latch means 163 in FIG. 24 represents its cocked condition and the condition of the latch means in FIG. 25 represents its released condition.

A mandrel 176 is mounted on the carriage 134 and arranged to cooperate with the clamp 132. Specifically, when the clamp 132 is in its document-engaging position, the clamp holds a document against the upper surface 176' of the mandrel 176. When a document 124 has been moved by the clamp 132 and carriage 134 to the position illustrated in FIG. 24 and the clamp 132 is moved to its document-releasing position, movement of the mandrel 176 and clamp 132 with the carriage 134 in the direction opposite to the arrow 136 will preferably not move the document 124. Thus, other means which will be described hereinafter is preferably provided for moving the document from its FIG. 24 position in the direction of the arrow 136 and out ofthe system 122.

The carriage 134 is shown in its starting position in FIG. 23. From this position, the carriage 134 will move in the direction of the arrow 136 in a-step-by-step manner as mentioned previ ously. That is, control means must be provided for stopping movement of the carriage 134 at selected positions along its path of movement. In FIG. 23, I have shown a plurality of pins 178 which are carried in a selector bar or program bar 179 which extends parallel to the guide bar 138 on which the carriage 134 reciprocates. As best seen in FIG. 27, the selector bar 179 is inserted into a dovetail groove formed in a bar 180 fastened to the floor 181 of the housing for the system 122. Further, the bar 179 is provided with a knob 182 (FIGS. 12 and 23) so that an operator may remove the bar by pulling it from the system 122 in the direction opposite to the arrow 136.

Each pin 178 carried by the bar 179 represents the position ofa line of data on the document. Thus, the position ofthe bar 179 is critical. In order to provide assurance that the bar 179 is in its proper position, a switch 183 (FIGS. 23 and 35) is arranged to sense the position of the bar.

The bar 179 is referred to as a selector bar or program bar because the pins 178 carried by the bar will, respectively, determine the points at which the carriage 134 will stop movement in the direction of the arrow 136 so that a line of data on a document can be scanned. Thus, an operator may have several different program bars 179, one bar for each particular document to be scanned.

Each pin 178 constitutes an actuator for a switch means. In the illustrative embodiment, as best seen in FIG. 27, each pin 178 is arranged to block light projected at a light-responsive device 184 carried by an arm 185 extending outwardly from the carriage 134. A light source 186 is also carried by the arm 185, the device 184 being on one side of the row of pins 178 and the light source 186 being on the opposite side of the row of pins. Conventionally, the light source 186 is arranged to project light at the device 184. When the carriage 134 moves so that a pin 178 is between the light source 186 and the lightresponsive device 184, the light-responsive device will change state electrically. By operatively connecting the device 184 to the drive means for the carriage 134, as will be more fully discussed hereinafter, I can just stop the carriage 134 at locations determined by the positions of the pins 178.

The bar 179 is, therefore, a support member or support means for the switch-actuating pins 178 and the arm is a frame which carries a switch means which is operated by the pins 178. While, in the illustrative embodiment, I have shown a light-actuated semiconductor device 184 and a light source 186 cooperating therewith as the switch means, it will be appreciated that I may mount a mechanically operated switch on the arm 185 so that the switch will be mechanically operated by each of the pins 178.

Referring now to FIG. 28, it will be seen that I have illustrated a program bar 179 which carries a plurality of horizontally extending pins 178. In the embodiment of FIG. 28, the light source 186' is disposed above and in vertical registry with the row of pins 173' and the light-responsive device 184 is disposed below and in vertical registry with the row of pins. The arrangement of FIG. 28 is provided so that the program bar 179 may be used with a pin setting mechanism, such as that indicated generally by the reference numeral 188 in FIG. 29. This pin setting mechanism 188 comprises a support member 190 which extends parallel to the guide member 180 which is parallel to the path of movement of the light source 186' and the light-responsive device 184'. A plurality of horizontally extending pins 191 (only one of which is shown) is reciprocably mounted in horizontally extending'openings 192 in the member. The pins 191 are longitudinally spaced apart in the member 191) to define a plurality of stopping positions for the carriage 134. A knob 193 is connected to each pin 191 to provide means for moving each pin into the space between the light source 186' and the light-responsive device 184'. That is, an operator can move a knob 193 from its illustrated solid-line position to its illustrated broken-line position to move the pin 191 connected thereto into a position which will block the light projected at the device 184' when the device is adjacent the pin. The travel of each knob 193 is determined by the abutment portions 194, 195 of the member 190.

Preferably, the member 190 will be fabricated from a plastic material, such as nylon, and each opening 192 will be formed snugly to engage the pin 191 extending therethrough to provide a slight frictional resistance to the movement of the pin. Thus, a pin 191 will stay in its manually adjusted position until affirmatively moved.

A particular program bar 179 may be provided with openings, such as indicated at 196, through which a pin 191 may extend. That is, an operator may select a program bar 179' which has a plurality of fixed pins 178 disposed therealong. If it is desired that the carriage be stopped at a position other than a position corresponding to one of the fixed pins 178, a pin 191 can be moved through an opening 196 in the bar 179 to stop the carriage at the desired location. Of course, the bar 179' can be completely removed and the positions at which the carriage will stop can be established by moving selected knobs 193 and the pins 191 connected, respectively, thereto from the right to the left as viewed in FIG. 29.

In order to utilize the pin setting mechanism 188, an opening (not shown) in the housing for the system 122 must be provided so that an operator can gain access to the knobs 193.

In the illustrative embodiment of FIG. 12, I have shown a row of knobs 208 which are the knobs of a pin setting mechanism 203 which I will now discuss. The mechanism 203 is illustrated in FIGS. 30, 31, 32 and 33. 

1. A system for scanning data on a document comprising a scanning head arranged for transverse movement relative to such a document, drive means for providing relative longitudinal movement between said scanning head and such a document, control means for said drive means, said control means including first switch means for deenergizing said drive means to stop such relative movement, and a plurality of switch actuating means longitudinally spaced apart to define a plurality of preselected relative positions for said scanning heAd and such a document, each of said actuating means being arranged to actuate said first switch means.
 2. The system of claim 1 in which said control means includes means for finding a transversely extending line of data to be scanned, said finding means including means for detecting the presence of a line of data on such a document and deenergizing said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line.
 3. The system of claim 2 in which said detecting and deenergizing means is disposed in series with said first switch means, whereby, when said first switch means is actuated by one of said actuating means and said detecting means simultaneously detects the presence of a line of data corresponding to said one actuating means, said drive means will be deenergized.
 4. The system of claim 2 in which said detecting and deenergizing means includes electro-optical means for detecting indicia printed on a document.
 5. The system of claim 2 in which said detecting and deenergizing means includes a light source arranged to direct light at such a document, a light-actuated semiconductor device and optical means for projecting the light reflected from such a document toward said semiconductor device.
 6. The system of claim 5 in which said first switch means includes a first relay and means cooperatively associated with said actuating means and effective to operate said first relay, and including a second relay operatively connected to and operated by said semiconductor device, said first and second relays being connected in series, whereby, when said first switch means is actuated by one of said actuating means and said detecting means simultaneously detects the presence of a line of data corresponding to said one actuating means, said first and second relays will be operated to deenergize said drive means.
 7. The system of claim 6 including a third relay effective, when deenergized, to maintain said drive means energized, said third relay being connected to the series circuit of said first and second relays, whereby, when said first and second relays are simultaneously operated, said third relay is energized to deenergize said drive means.
 8. The system of claim 1 in which said drive means is arranged to move such a document longitudinally past said scanning head.
 9. The system of claim 1 in which said drive means is arranged to move such a document longitudinally past said scanning head, and in which said control means includes means for finding a transversely extending line of data to be scanned, said finding means including means for detecting the presence of a line of data on such a document and deenergizing said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line.
 10. The system of claim 9 in which said detecting and deenergizing means is disposed in series with said first switch means, whereby, when said first switch means is actuated by one of said actuating means and said detecting means simultaneously detects the presence of a line of data corresponding to said one actuating means, said drive means will be deenergized.
 11. The system of claim 1 in which said drive means is arranged to move such a document longitudinally past said scanning head, said drive means including a carriage arranged for longitudinal reciprocation relative to said scanning head, and clamp means carried on said carriage and arranged to clamp such a document for movement therewith.
 12. The system of claim 11 in which said clamp means includes a clamp member mounted on said carriage for movement between a document engaging position and a document releasing position, spring means for yieldably urging said clamp member to its document engaging position, latch means for holding said clamp member in its document releasing position in opposition to said spring means, said latch means being supported by said carriagE, means for cocking said latch means, said cocking means being disposed adjacent one end of the travel of said carriage, and means for releasing said latch means, said releasing means being disposed adjacent the opposite end of the travel of said carriage.
 13. The system of claim 12 in which said cocking means includes an abutment disposed in the path of movement of said latch means and arranged to cock said latch means when said carriage reaches said one end of its travel.
 14. The system of claim 12 in which said releasing means includes a solenoid effective, when energized, to release said latch means.
 15. The system of claim 13 in which said releasing means includes a solenoid arranged, when energized, to release said latch means.
 16. The system of claim 11 in which said clamp means includes a clamp member mounted on said carriage for pivotal movement between a document engaging position and a document releasing position, a pinion gear rigidly connected to said clamp member and journaled on the pivot axis thereof, a spur gear journaled on said carriage and meshed with said pinion gear, spring means for yieldably urging said spur gear in one direction about its axis to hold said clamp member in its document engaging position, latch means for holding said spur gear in opposition to said spring means, thereby to hold said clamp member in its document releasing position, means for cocking said latch means to hold said clamp member in its document releasing position, said cocking means being disposed on one side of the transverse path of movement of said scanning head, and means for releasing said latch means so that said clamp member can be moved to its document engaging position, said releasing means being disposed on the opposite side of said transverse path.
 17. The system of claim 16 in which said cocking means includes an abutment disposed in the path of movement of said latch means and arranged to cock said latch means when said carriage reaches one end of its travel and in which said releasing means includes a solenoid-operated device effective, when energized, to release said latch means.
 18. The system of claim 17 including means for detecting the presence of a document and energizing said solenoid-operated device when such a document is in a position to be engaged by said clamping means.
 19. The system of claim 18 in which said detecting and energizing means includes a light-actuated semiconductor device operatively connected to said solenoid-operated device, a light source arranged to project light at said semiconductor device, said light source and said semiconductor device being positioned so that, when such a document is in a position to be engaged by said clamp, the document is effective to block the light projected at the semiconductor device, thereby to establish a circuit condition effective to energize said solenoid-operated device.
 20. The system of claim 19 including a solenoid-operated stop arranged to position such a document to be engaged by said clamping means, said solenoid-operated stop being movable, when energized, to a position out of the path of movement of such a document, said semiconductor device being operatively connected to and effective to energize said solenoid-operated stop.
 21. The system of claim 12 including a frictional drive roller for engaging and moving such a document longitudinally past said scanning head, said drive roller being drivingly connected to said drive means and positioned and arranged to continue to move such a document longitudinally after said clamp member is moved to its document releasing position and said carriage is returned toward said other end of its travel.
 22. The system of claim 1 including a support member extending in the direction of relative movement between said scanning head and such a document, each of said switch actuating means being a pin carried by said support member.
 23. The system of claim 22 in which said first switch means includes a frame, a light-actuatEd semiconductor device and a light source arranged to direct light at said semiconductor device, said light source and said semiconductor device being mounted on said frame, said frame being arranged for movement along and relative to said support member with said light source on one side of said pins and said semiconductor device on the opposite side of said pins, each pin being proportioned and designed, when said semiconductor device is adjacent thereto, to block the light directed thereat by said light source.
 24. The system of claim 23 in which each of said pins is selectively movable between an operative position effective, when said semiconductor device is adjacent thereto, to block the light directed thereat by said light source, and an inoperative position which is not effective to block the light directed at the semiconductor device.
 25. The system of claim 24 including a pushbutton associated with each of said pins and linkage means arranged to connect each of said pins to its associated pushbutton and to move said pin transversely to the direction of relative movement between said scanning head and such a document.
 26. The system of claim 23 in which said support member is a bar and in which each of said pins is selectively slidably movable in said bar between an operative position effective, when said semiconductor device is adjacent thereto, to block the light directed thereat by said light source, and an inoperative position which is not effective to block the light directed at the semiconductor device.
 27. The system of claim 25 including a housing for said system, said housing having an aperture associated with each of said pins, a visual indicating means operatively connected to each of said pins to indicate the position thereof, each of said last-mentioned means being adjacent one of said apertures.
 28. The system of claim 27 in which each of said visual indicating means comprises a movable member having a first position corresponding to the operative position of its associated pin and a second position corresponding to the inoperative position of its associated pin, each of said movable members having its first and second portions alternatively visible through the adjacent aperture.
 29. The system of claim 25 including manually operated means for moving said pins to their respective inoperative positions, said manually operated means being operatively connected to said linkage means.
 30. The system of claim 1 including transversely extending guide means for said scanning head, energy storage means for urging said scanning head toward its starting position and along said guide means, means for moving said scanning head along said guide means and in opposition to said energy storage means, said moving means comprising a pair of spaced apart support means, an endless, flexible means trained about said support means, at least one of said support means being rotatable and drivingly connected to said flexible means, said support means being positioned to support one run of said flexible means for movement in a direction substantially along said guide means, a pusher carried by said flexible means, a hook member arranged to extend into the path of said pusher defined by said one run, means for mounting said hook member on said scanning head, whereby, when said hook member is engaged by said pusher, said scanning head will be moved away from its starting position and along said guide means, said hook member being proportioned and designed so that, when said pusher starts to move about said support means at the end of said one run remote from the starting position of said scanning head, said hook member will disengage the pusher so that said scanning head will be returned to its starting position.
 31. The system of claim 30 in which said mounting means is arranged so that said hook member is movable on said scanning head between a first position in the path of said pusher and a second position out of the path of said pusher, said hook membeR being biased toward its second position, and means, adjacent the starting position of said scanning head, for moving said hook member from its second position to its first position.
 32. The system of claim 31 including a solenoid cooperatively connected to said hook member and arranged, when energized, to move said hook member from its first position to its second position, thereby to disengage said pusher.
 33. The system of claim 32 including code reading and detecting means carried by said scanning head and operatively connected to said solenoid, said reading and detecting means being effective to energize said solenoid upon detecting a coded indicia printed on such a document and representing the end of a line of data to be read.
 34. The system of claim 33 including means for inhibiting said code reading and detecting means when said solenoid is energized and said scanning head is being returned to its starting position.
 35. The system of claim 1 in which said scanning head comprises a frame, a light source carried by said frame and arranged to project light at such a document, a light-actuated semiconductor device carried by said frame, and optical means carried by said frame and arranged to project the light reflected from such a document toward said semiconductor device.
 36. The system of claim 35 in which the axis of said light source is disposed at an angle of approximately 45* to such a document and the optical axis of said optical means is disposed substantially perpendicularly to such a document.
 37. The system of claim 35 in which the axes of said light source and said optical means lie in a transverse plane which is perpendicular to such a document and which includes the transverse path of movement of said scanning head.
 38. The system of claim 37 in which said optical means includes a diaphragm having a slit elongated in a direction substantially perpendicular to the transverse path of movement of said scanning head, said slit being effective to concentrate reflected light on a particular portion of said semiconductor device.
 39. The system of claim 38 in which said control means includes means for finding a transversely extending line of data to be scanned, said finding means including means for detecting the presence of a line of data on such a document and deenergizing said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line, said detecting and deenergizing means including a second light source carried by said frame and arranged to project light at such a document, a second light-actuated semiconductor device carried by said frame and second optical means carried by said frame and arranged to direct light reflected from such a document toward said second semiconductor device.
 40. The system of claim 39 in which the axis of said second light source is disposed substantially perpendicularly to the axis of the first-mentioned light source, the axis of said second optical means is disposed substantially perpendicularly to such a document, said first-mentioned semiconductor device, said second semiconductor device, said first-mentioned light source and said second light source being disposed on the same side of such a document, and all of said axes lie in said transverse plane.
 41. The system of claim 40 in which said second optical means includes a diaphragm having a slit elongated in a direction substantially parallel to the transverse path of movement of said scanning head, this last-mentioned slit being effective to concentrate reflected light on a particular portion of said semiconductor device.
 42. The system of claim 39 in which the axis of said second light source is disposed substantially perpendicularly to the axis of the first-mentioned light source, the axis of said second optical means is disposed substantially perpendicularly to such a document, said first-mentioned semiconductor device, said second semiconductor devIce, said first-mentioned light source and said second light source being disposed on the same side of such a document, and all of said axes lie in said transverse plane.
 43. The system of claim 42 in which said second optical means includes a diaphragm having a slit elongated in a direction substantially parallel to the transverse path of movement of said scanning head, this last-mentioned slit being effective to concentrate reflected light on a particular portion of said second semiconductor device.
 44. A system for scanning and optically reading transversely extending lines of data on a document comprising a scanning head arranged for transverse movement relative to such a document and along such a line of data, drive means for providing relative longitudinal movement between said scanning head and such a document, control means for said drive means, said control means including means for finding a transversely extending line of data to be scanned, said finding means including electro-optical means for detecting the presence of a line of data on such a document and operating said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line, said electro-optical means being longitudinally stationary relative to said scanning head, said electro-optical means including a light source arranged to project light at such a document, a light-actuated semiconductor device, and optical means for projecting the light reflected from such a document toward said semiconductor device.
 45. The system of claim 44 in which said drive means is arranged to move such a document longitudinally past said scanning head, said drive means including a carriage arranged for longitudinal reciprocation relative to said scanning head, and clamp means carried on said carriage and arranged to clamp such a document for movement therewith.
 46. The system of claim 44 including transversely extending guide means for said scanning head, energy storage means for urging said scanning head toward its starting position and along said guide means, means for moving said scanning head along said guide means and in opposition to said energy storage means, said moving means comprising a pair of spaced apart support means, an endless, flexible means trained about said support means, at least one of said support means being rotatable and drivingly connected to said flexible means, said support means being positioned to support one run of said flexible means for movement in a direction substantially along said guide means, a pusher carried by said flexible means, a hook member arranged to extend into the path of said pusher defined by said one run, means for mounting said hook member on said scanning head, whereby, when said hook member is engaged by said pusher, said scanning head will be moved away from its starting position and along said guide means, said hook member being proportioned and designed so that, when said pusher starts to move about said support means at the end of said one run remote from the starting position of said scanning head, said hook member will disengage the pusher so that said scanning head will be returned to its starting position.
 47. The system of claim 44 in which the axes of said light source and said optical means lie in a transverse plane which is perpendicular to such a document and which includes the transverse path of movement of said scanning head, the axis of said light source being inclined relative to the axis of said optical means within said transverse plane.
 48. The system of claim 44 in which said drive means includes an electrically operated motor and means for engaging such a document, said engaging means being drivingly connected to said motor and arranged to move such a document longitudinally past said scanning head, and in which said control means includes circuit means for operatively connecting said semiconductor device to said drive means.
 49. The system of claim 48 includinG second drive means for transversely reciprocating said scanning head relative to such a document and along and above lines of data thereon, said control means including additional circuit means for operating said second drive means, said additional circuit means being cooperatively associated with said first-mentioned circuit means and effective, when said first-mentioned circuit means stops such relative longitudinal movement, to start said second drive means to move said scanning head along and above a corresponding line of data.
 50. A system for reading graphically printed data disposed in transverse lines on a document, said system comprising a scanning head arranged for transverse movement relative to such a document, means for moving said scanning head along a line of data at a constant, predetermined speed, light source means carried by said scanning head and arranged to project light at such a line of data on such a document, a light-responsive semiconductor device carried by said scanning head, optical means for projecting light reflected from such a document toward said semiconductor device, said optical means being carried by said scanning head, whereby the concentration of light on said semiconductor device depends on the presence or absence as well as the width and spacing of graphical symbols in the line of data being scanned, an output device, and circuit means for operatively connecting the semiconductor device to said output device.
 51. The system of claim 50 in which the axis of said light source is disposed at an angle of approximately 45* to such a document and the optical axis of said optical means is disposed substantially perpendicularly to such a document.
 52. The system of claim 51 in which the axes of said light source and said optical means lie in a transverse plane which is perpendicular to such a document and which includes the transverse path of movement of said scanning head.
 53. The system of claim 52 in which said optical means includes a diaphragm having a slit elongated in a direction substantially perpendicular to the transverse path of movement of said scanning head, said slit being effective to concentrate reflected light on a particular portion of said semiconductor device.
 54. The system of claim 52 including drive means for providing relative longitudinal movement between said scanning head and such a document, and control means for said drive means, said control means including means for finding a transversely extending line of data to be scanned, said finding means including means for detecting the presence of a line of data on such a document and deenergizing said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line, said detecting and deenergizing means including a second light source carried by said frame and arranged to project light at such a document, a second light-actuated semiconductor device carried by said frame and second optical means carried by said frame and arranged to direct light reflected from such a document toward said second semiconductor device.
 55. The system of claim 50 including drive means for providing relative longitudinal movement between said scanning head and such a document, and control means for said drive means, said control means including means for finding a transversely extending line of data to be scanned, said finding means including means for detecting the presence of a line of data on such a document and deenergizing said drive means to stop relative movement between said scanning head and such a document, whereby said scanning head can scan such a line, said detecting and deenergizing means including a second light source carried by said frame and arranged to project light at such a document, a second light-actuated semiconductor device carried by said frame and second optical means carried by said frame and arranged to direct light reflected from such a document towArd said semiconductor device.
 56. The system of claim 55 in which said drive means includes a servomotor, and in which said control means includes a servoamplifier, the input of which is operatively connected to the output of said second semiconductor device, whereby said drive means is effective continually to position such a document so that a line of data on the document is always directly under the scanning head irrespective of any skew of the line.
 57. The system of claim 55 in which said means for moving said scanning head includes second drive means for transversely reciprocating said scanning head, in which said control means includes circuit means for operatively connecting said second semiconductor device to said first-mentioned drive means and additional circuit means for controlling said second drive means, said additional circuit means being cooperatively associated with said first-mentioned circuit means and effective, when said first-mentioned circuit means stops such relative longitudinal movement, to start said second drive means to move said scanning head along and above a corresponding line of data on such a document.
 58. The system of claim 57 in which the axis of said second light source is disposed substantially perpendicularly to the axis of the first-mentioned light source, the axis of said second optical means is disposed substantially perpendicularly to such a document, said first-mentioned semiconductor device, said second semiconductor device, said first-mentioned light source and said second light source being disposed on the same side of such a document, and all of said axes lie in said transverse plane.
 59. The system of claim 50 in which said circuit means includes means for registering a predetermined code representing the end of a line of data to be scanned and providing a predetermined output effective, when coupled to said moving means for said scanning head, to cause said scanning head to be returned to its initial starting position. 